In zero voltage switching (ZVS) power converter topologies, for example, fast turn-off of the power MOSFET is very important. Power MOSFETs must be turned "off" before their drain-source capacitance is charged significantly by the current being commutated "off". Fast FET turn-on in ZVS power converter topologies is of lesser concern since self-commutation in the turn-on process is inherent in the operation of these topologies.
The possibility of spurious turn-on in high power MOSFET gate drive circuits becomes of increasing concern as switching speed and circuit power level grow, particularly in bridge-type topologies. High current switching paths and parasitic couplings from high voltage commutation injects spurious voltage spikes into the gate circuits. When the gates require the isolation provided by transformers, leakage inductances inherent in the windings increases the noise susceptibility problems as well as reduces switching speed. Under dynamic operational conditions instantaneous noise levels may rise sufficiently to turn the MOSFETs "on" at inappropriate times. Catastrophic circuit failure, primarily due to cross conduction, may then result.